Just ahead of U.S. sanctions on Iran set to snap back on Monday targeting primarily the energy, shipbuilding, shipping, and banking sectors, Iran's most prominent conservative cleric has announced that if oil exports are halted, Saudi tankers will be confiscated and Gulf countries attacked.

Powerful Shia cleric Ayatollah Ahmad Alamolhoda is the Friday Prayer leader in Mashhad, considered Iran's spiritual capital and among the holiest places in Shia Islam, and sits on the government's "Assembly of Experts" but has no formal government role or decision-making ability. However, he's a powerful leader and chief spiritual force behind Iran's conservative faction who has long been at odds with President Hassan Rouhani.